1. Field of Invention
The present invention relates to medical uses of the levo-oxiracetam and oxiracetam, particularly to use of levo-oxiracetam and oxiracetam in preparation of medicines for preventing or treating coma.
2. Description of the Related Art
Oxiracetam (oxiracetam), is a nootropic drug that first synthesized in 1974 by the Italian pharmaceutical company, ISF S.P.A., the drug get into the Italian market in 1987. Oxiracetam is a racemic composition including two isomers (S)-oxiracetam and (R)-oxiracetam. Reports about oxiracetam shows that oxiracetam, which can promote brain ATP, promote synthesis of acetylcholine, enhances nerve conduction, hypoxia-induced retrograde amnesia improvement effect and memory, and improve learning ability, is the treatment of Alzheimer-type dementia (AD), vascular dementia (VD), etc. disorders of effective drugs.
L-oxiracetam ((S)-4-hydroxy-2-oxo-pyrrolidineacetamide) is of levo type of oxiracetam (CAS 62613-82-5), white microcrystalline powder with melting point at 135-136° C. and optical rotation of −36.0° (C=1.00 in water). The solubility of L-oxiracetam is significantly better than the racemate. There is no reports indicates that L-oxiracetam currently is used as a single drug.
CN 101367757A discloses a preparation method of (S)-4-hydroxy-2-oxo-1-pyrrolidineacetamide preparation. It uses (S)-4-halo-3-hydroxybutyric acid ester as a raw material in a polar solvent and under basic conditions to produce L-oxiracetam. The basic conditions means that the reaction is carried through increasing alkali in the course of the reaction, and dropping chlorides to control the pH value. The crude product obtained by using the cation exchange resin is an acidic aqueous solution of the product, and then using an anion exchange resin to neutralize the acidic solution, and the neutralized solution was concentrated to get the crude product and the crude product was recrystallized by ethanol once with methanol/acetone mixed solvent of crystallization or recrystallization from isopropanol once a process for preparing L-oxiracetam.
Coma is the most serious disturbance of consciousness due to the high suppression of lower cortical and subcortical reticular structure, that is, a sustained interruption or most highly suppressed state of complete loss of consciousness of the highest nervous activities, and a serious condition in patients with complete loss of consciousness. Alcoholism is one of three causes of coma. With the accelerated pace of modem life and people's increasing mental stress, alcoholics increasingly appeared, the phenomena of being drunk and alcohol coma are increasingly more common Trauma-induced coma is one of the three causes of coma occurred today in a car accident, falls and other trauma-induced coma and is also more common Anesthesia-induced coma for today is a common medical malpractice. Some patients could not wake up and no perception after anesthesia. Anesthesia-induced coma is one of the three causes of coma. How to further improve the cure rate awaking coma to reduce mortality and improve the level of arousal and cognitive function is a major issue facing today, to solve this problem would have important practical significance.